How To Extract a Unit Value from a Date and Time?

Answer

If you want to extract a specific date or time unit value out of a date or a time, you can use the EXTRACT(unit FROM expression) function. The tutorial exercise below gives you some good examples:

ELECT EXTRACT(DAY FROM NOW()) FROM DUAL;
28

ELECT EXTRACT(HOUR FROM NOW()) FROM DUAL;
23

ELECT EXTRACT(SECOND FROM NOW()) FROM DUAL;
36